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HTML Block – HTML produced by an expression

The HTML block renders the HTML an expression produces. It is the last resort for content the other blocks cannot show – a formatted mail body, a small table built from data, markup an interface delivers.

This page is part of the form block reference.

1. At a glance
Purpose Renders HTML
Typical use The body of an incoming mail, a formatted text field, a small overview built with an expression
Related Label Block, Element Block

2. Settings

Setting Meaning Default / required
"Content" The HTML to render, as a text expression Required. Without it the block is empty.
"Isolate HTML" Shows the HTML in a frame of its own instead of inserting it into the form off
"Auto Refresh", "Refresh Interval (s)" Evaluates the content again on a clock of its own, every given number of seconds off, 30

In addition, the block has the settings every block has, except "Flush".

3. Behaviour

  • HTML entities in the result (<, &) are decoded before the content is rendered.
  • The content is not checked. Whatever the expression produces is inserted into the page as it is. Never build it from input that users or external systems can control without cleaning it first – it could change the page or run scripts in the browser of everyone who opens the form.
  • "Auto Refresh" works as on the Label Block.

Isolated HTML

With "Isolate HTML" switched on, the content is shown in a frame of its own:

  • Styles inside the HTML only apply inside the frame. A mail or a document from another system that brings its own CSS cannot change the rest of the form.
  • The standard styles of nexxcite are loaded into the frame, so its CSS classes and the colour tokens (rgb(var(--nx-ink))) work there as well and follow the light or dark mode. The stylesheets of the form, of the global settings and of roles do not reach the frame.
  • The frame grows and shrinks with its content.
  • The frame is transparent: the background of the block shows through, unless the HTML sets its own.
  • Scripts and forms inside the HTML do not run. Links open in a new browser tab.

4. Example

A short overview. "Content" = a text expression that produces <b>3</b> open tasks, next due on <b>24.10.</b> from the record. For a single value, a label with a bold font weight is simpler.

5. Limitations

  • Prefer the other blocks wherever they can show the content: their styling settings, visibility and accessibility work without markup.
  • With "Isolate HTML", colours defined in a theme do not reach the frame – it uses the built-in colours of the light or dark mode.